Resection tools and related methods of use

ABSTRACT

A device for treating tissue may include a tissue expander configured to be inserted into a body lumen and stretch tissue surrounding the body lumen, and a tool configured to be coupled to the tissue expander and move along a path defined by the tissue expander.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This patent application is a continuation of U.S. application Ser. No.15/382,124, filed Dec. 16, 2016, which claims the benefit under 35U.S.C. § 119 to U.S. Provisional Patent Application No. 62/269,556,filed on Dec. 18, 2015, the entireties of which are incorporated hereinby reference.

TECHNICAL FIELD

Examples of the present disclosure relate to resection tools and relatedmethods of use.

BACKGROUND

Colorectal cancer is a leading cause of death in the United States. Onetreatment option for the removal of malignant and pre-malignant lesionsis endoscopic mucosal or en bloc resection. Resections can allow for thepathological determination of tissue health.

In order to remove the tissue, the surgeon often carefully cuts throughthe mucosa and submucosa, a process which is time consuming anddifficult as the tissue easily deforms and deflects when pressure isapplied. Other challenges include difficulty in locating the submucosallayer, maintaining an adequate lift height for a duration long enough toperform the resection, difficulty injecting the lifting solution throughconventional injection needles, and repeatedly exchanging devicesthrough an endoscope.

SUMMARY

In one aspect, the present disclosure is directed to a medical device.The device may include a tissue expander configured to be inserted intoa body lumen and lift tissue surrounding the body lumen, and a toolconfigured to be coupled to the tissue expander and move along a pathdefined by the tissue expander.

The tissue expander may include a first support ring and a secondsupport ring, wherein the path may be defined at a first end by thefirst support ring and at a second end by the second support ring, andwherein the tool may be configured to move circumferentially along thepath. The device may include one or more spacers disposed between thefirst support ring and the second support ring, wherein the one or morespacers may be longitudinally expandable. The tool may include a firstattachment portion configured to be coupled to the first support ring,and a second attachment portion configured to be coupled to the secondsupport ring, wherein a length of the tool between the first attachmentportion and the second attachment portion may be equal to a length ofthe one or more spacers. The first attachment portion may include afirst mating feature, the second attachment portion may include a firstmating feature, the first support ring may include a second matingfeature disposed on at least one of a proximally-facing surface and adistally-facing surface, and the second support ring may include asecond mating feature disposed on at least one of a proximally-facingsurface and a distally-facing surface, wherein the first mating featureof the first attachment portion may be complementary to the secondmating feature of the first support ring, and wherein the first matingfeature of the second attachment portion may be complementary to thesecond mating feature of the second support ring. One of the firstmating feature and the second mating feature may be a recess, and theother of the first mating feature and the second mating feature may be apin, bearing, ball, protrusion, wheel, or roller configured to bereceived by the recess. The tool may include a cutting member extendingradially outward when the tool is coupled to the tissue expander. Thetissue expander may include anchoring features extending radiallyoutward from an outer circumferential surface.

In another aspect, the present disclosure is directed to a medicaldevice. The device may include a first support, and a plurality of legassemblies coupled to the first support, wherein the plurality of legassemblies may be circumferentially arranged about a centrallongitudinal axis of the device, wherein at least one pair of adjacentleg assemblies may be separated from one another by a first angledefined in a plane that is normal to the central longitudinal axis ofthe device, and wherein remaining pairs of adjacent leg assemblies maybe separated from one another by second angles defined in the plane thatare less than the first angle. Each of the plurality of leg assembliesmay include a first pivot joint connecting a corresponding leg assemblyto the first support; a first leg extending from the first pivot joint,the first leg being configured to pivot relative to the first supportvia the first pivot joint, a second pivot joint disposed at a distal endof the first leg, and a second leg extending distally from the secondpivot joint, the second leg being configured to pivot relative to thefirst leg via the second pivot joint.

Distal ends of each of the second legs may be unconnected to oneanother, the first angle may be from 80 degrees to 120 degrees, and eachof the second angles may be from 20 degrees to 60 degrees. The first legand the second leg of each of the plurality of leg assemblies may besubstantially parallel to the central longitudinal axis when the deviceis in a collapsed configuration. The device may be movable to anexpanded configuration, wherein in the expanded configuration, the firstleg of each of the plurality of leg assemblies may be transverse to thecentral longitudinal axis, and the second leg of each of the pluralityof leg assemblies may be substantially parallel to the centrallongitudinal axis. The device may further include a second supportdisposed proximally of the first support, and a plurality of linkagesextending from the second support, wherein at least one linkage of theplurality of linkages may be coupled to each first leg of the pluralityof leg assemblies, wherein, when a proximal force is applied to thesecond support, the second support may move proximally relative to thefirst support to cause the linkages to pull proximally on each first legof the plurality of leg assemblies, causing each first leg to pivotproximally via its respective first pivot joint, and moving the deviceto the expanded configuration. The first support and the second supportring each may include a lumen, and wherein the lumens of the firstsupport and the second support may be aligned to enable the passage ofan endoscope through the lumens. Each first pivot joint may include alocking mechanism configured to limit a proximal retraction of arespective first leg.

In yet another aspect, the present disclosure is directed to a method ofmanipulating tissue. The method may include stretching tissue with atissue expander to define body lumen, positioning a tool relative to thetissue expander, and moving the tool along a path defined by the tissueexpander.

The tissue expander may include a first support ring and a secondsupport ring, wherein the path defined by the tissue expander may be acircumferential path defined at a first end by the first support ring,and at a second end by the second support ring. The method may include,before the using step, positioning the second support ring distal to atargeted treatment area, and positioning the first support ring proximalto the targeted treatment area, wherein the stretched tissue may includethe targeted treatment area disposed between the first support ring andthe second support ring. The tool may include a cutting member, andmoving the tool along the path defined by the tissue expander may removea portion of the stretched tissue defining the body lumen. The bodylumen may be located within a colon.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate various examples and togetherwith the description, serve to explain the principles of the disclosedexamples.

FIG. 1 is a side view of a tissue expander according to an example ofthe present disclosure.

FIG. 2 is an end view of the tissue expander of FIG. 1.

FIG. 3 is a schematic view of a removal tool according to an example ofthe present disclosure.

FIGS. 4-6 are in vivo illustrations of a method of inserting the tissueexpander of FIG. 1 into a body lumen.

FIG. 7 is an in vivo illustration of the tissue expander of FIG. 1 andthe removal tool of FIG. 3 within a body lumen.

FIG. 8 is a perspective view of a tissue expander in a collapsedconfiguration according to another example of the present disclosure.

FIG. 9 is an end view of the tissue expander of FIG. 8 in the collapsedconfiguration.

FIG. 10 is a side view of the tissue expander of FIG. 8 in the collapsedconfiguration.

FIG. 11 is a perspective view of the tissue expander of FIG. 8 in anexpanded configuration.

FIG. 12 is an end view of the tissue expander of FIG. 8 in the expandedconfiguration.

FIG. 13 is a side view of the tissue expander of FIG. 8 in the expandedconfiguration.

DETAILED DESCRIPTION

Reference will now be made in detail to examples of the presentdisclosure, which are illustrated in the accompanying drawings. Whereverpossible, the same reference numbers will be used throughout thedrawings to refer to the same or like parts or components. The term“distal” refers to the direction that is away from the user or operatorand into the patient's body. By contrast, the term “proximal” refers tothe direction that is closer to the user or operator and away from thepatient's body.

In at least some examples, the present disclosure is directed tosystems, devices, and methods used to facilitate endomucosal or en blocresection of colorectal or other tissues. Some components of the systemmay be used to stretch and hold tissue walls (e.g., the colorectal wall)in a regular cylindrical shape or other suitable shape for resection oftissue. Other components of the system may help perform the actualresection by slicing and/or removing tissue.

A tissue expander 100 is shown in FIG. 1 in an expanded configuration.The tissue expander 100 may include a first support 102 and a secondsupport 104. First support 102 may be a circular ring in one example,although first support 102 may include other suitable cross-sectionalconfigurations such as, e.g., ovular, rectangular, or the like. Firstsupport 102 may be formed of any suitable biocompatible material suchas, e.g., metals, alloys, plastics, or the like. The first support 102may be biased toward the expanded configuration such that when aconstraining force is removed from the first support 102, the firstsupport 102 urges itself toward the expanded configuration. Thus, insome examples, first support 102 may be formed of a shape memorymaterial such as, e.g., nitinol, that is set or pre-shaped into theexpanded configuration. The first support 102 also may radially expandby another suitable mechanism, such as, e.g., by a ratcheting mechanism.For example the supports 102 and 104 could be linear pieces of metal.One end of each support 102, 104, may have ratcheting teeth or slots cutinto it that slide into a receiver on the other end, thus forming acircular ring. The ring could then be expanded by or collapsed byactuating the teeth through the receiver. Actuation could be achieved bya micro-mechanism (e.g., similar to a hose clamp). For example, byactuating a screw in the receiver, the toothed or slotted end may be fedthrough the receiver. In another example, the device could be designedsuch that the operator may use a direct force on the inside diameter ofthe ring to open the ring, which may remain in a locked state until arelease is activated on the receiver, at which point the ring maycollapse due to the natural elasticity of the lumen being treated. Inthe expanded configuration, first support 102 may have any suitablediameter, such as, e.g., 0.1 mm to 50 mm, although other suitable sizesare also contemplated. In some examples, a balloon may be used toinflate the first support 102 and the second support 104. In otherexamples, more than two support rings are also contemplated.

Referring to FIGS. 2 and 6, first support 102 may include aproximally-facing surface 106 and a distally-facing surface 108 (shownonly in FIG. 6). One or more of the proximally-facing surface 106 andthe distally-facing surface 108 may include mating features 110configured to interface with corresponding mating features 312 disposedon a removal tool 300 as set forth in further detail below. In oneexample, the mating features 110 may include a recessed track configuredto receive a protrusion, projection, roller, pin, ball, wheel, or othersuitable element that may ride within the track. The mating features 110may extend around an entirety of the proximally-facing surface 106 andthe distally-facing surface 108 to enable the corresponding matingfeatures 312 to translate around an entire circumference of an expandedbody lumen. In another example, mating feature 110 may be a railextending around the entirety of proximally-facing surface 106 and/ordistally-facing surface 108. In some examples, mating features 110and/or other portions of first support 102 may be magnetic, and may bemagnetically attracted to the corresponding mating features 312.

Second support 104 may be substantially similar to first support 102, ormay include one or more different features. First support 102 and secondsupport 104 may be arranged such that only proximally-facing surface 106of first support 102 includes mating features 110, while only thedistally-facing surface 108 of second support 104 includes matingfeatures 110. In other examples, the proximal-facing surface 106 and thedistally-facing surface 108 of both first support 102 and second support104 may include mating features 110.

Referring to FIG. 2, first support 102 and second support 104 each mayinclude an outer circumferential surface 112 and an innercircumferential surface 114. Outer circumferential surface 112 may bedisposed further from a radial center or a central longitudinal axis offirst support 102 or second support 104 than inner circumferentialsurface 114. In some examples, the outer circumferential surface 112 maybe the tissue-contacting surface of first support 102 or second support104. The outer circumferential surface 112 may be roughened, notched,slotted, etched, sand-blasted, coated or otherwise modified to provide abetter gripping surface and attachment to tissue walls surrounding abody lumen. In certain examples, inner circumferential surface 114 maybe directly coupled to one or more spacers 116 as set forth in furtherdetail below.

One or more spacers 116 may be disposed between first support 102 andsecond support 104. The spacers 116 may extend longitudinally betweenthe first support 102 and the second support 104. The spacers 116 may beformed of a shape memory material that it is set or pre-shaped into astraight and linear expanded configuration as shown in FIGS. 1 and 6.Each spacer 116 disposed between first support 102 and second support104 may be the same length, or may have slightly different lengths thanone another. In some examples, the spacers 116 may be removable from thefirst support 102 and the second support 104. As alluded to above, thespacers 116 may be directly coupled to the inner circumferential surface114 of the first support 102 and second support 104 such that matingfeature 110 on the proximally-facing surface 106 or distally-facingsurface 108 of the first support 102 and the second support 104 may notbe interrupted by the spacers 116.

In another example, spacers 116 may not be formed from a shape memorymaterial, but may instead be formed of a different biocompatiblematerial. For example, spacers 116 may be stiff and linear linkages. Inanother example, spacers 116 may be manually actuated by a screwmechanism or other similar mechanical mechanism to achieve a desireddistance between first support 102 and second support 104 in vivo. Inone example, each spacer 116 and only one of the supports 102 or 104 maybe threaded. The non-threaded support may be fixed to each spacer insuch a way that the spacer is allowed to rotate but not travellongitudinally. In the initial configuration, each spacer may extendbeyond the threaded support. By actuating the spacer clockwise orcounter-clockwise, the threaded support may travel longitudinally alongthe spacer until a limit is reached. In another example, each supportmay have spacer that connect to a hub. The two hubs may be threaded withopposite twists and connected by a single threaded actuator with amatching twist on each half. When the actuator is rotated clockwise orcounter-clockwise, the hubs may move closer together or father apart,forcing the supports connected by the spacers to move accordingly untila limit is reached. The spacing could be manually actuated or could beactuated by a piezoelectric motor or array of motors controlled by an exvivo driver. In another example, the distance between the support ringsmay be controlled by a zip-tie.

Spacers 116 may be attached to first support 102 and second support 104at circumferentially spaced locations to enable a removal tool 300(described below) to translate along a circumferential path disposedbetween adjacent spacers 116. The spacers 116 may be biasedlongitudinally outwardly to cause first support 102 and second support104 to separate. In the example shown in FIGS. 1 and 2, tissue expander100 includes four spacers 116 equally spaced apart from one another atapproximately 90 degree intervals, although other suitableconfigurations are also contemplated. For example, another suitablenumber of spacers 116 may be utilized to ensure the proper spacingbetween the first support 102 and the second support 104. In otherexamples, spacers 116 may be positioned at uneven intervals. Forexample, while four spacers 116 a-d are shown in FIG. 2, one or more ofthose spacers 116 may not be utilized. In one example, only two spacers(e.g., spacers 116 a and 116 c) spaced approximately 180 degrees fromone another may be used. In another example, spacer 116 d may be omittedsuch that three spacers 116 a-c are utilized. In this example, two pairsof adjacent spacers (e.g., spacers 116 a-116 b and 116 b-116 c) may bespaced approximately 90 degrees from one another, while another pair ofadjacent spacers (e.g., spacers 116 a-116 c) may be spaced 180 degreesfrom one another.

Spacers 116 may also include an undulating shape to allow forlengthening and/or compression to change the distance between twosupport rings and to increase the scaffolding area. The spacers 116 mayalso have a configuration in which they bow in or out, exposing a largersurface area and/or offering additional support between the supportrings.

Referring to FIGS. 1 and 2, first support 102 and second support 104each may include anchoring features 118 configured to maintain therelative positions of the first support 102 and second support 104 afterone, multiple, or all spacers 116 are removed from tissue expander 100in vivo. Anchoring features 118 may extend radially outward from theouter circumferential surface 112. In some examples, the anchoringfeatures 118 may be selectively deployable, removable, andbioabsorbable. That is, during insertion of tissue expander 100, theanchoring features 118 may not be in an active configuration such thatthe tissue expander 100 may be manipulated in vivo without excessivetrauma to tissue. The anchoring features 118 then may be deployed intothe tissue by any suitable mechanism, including, e.g., by manipulatingone or more latches, switches, or ratchets. Once a resection procedureis completed, the anchoring features 118 may be disengaged from firstsupport 102 and second support 104 by, e.g., a frangible link, so thatfirst support 102 and second support 104 can be removed withoutexcessive trauma to colorectal tissue. The anchoring features 118 mayremain in the body once the operation is completed, where they may beabsorbed and degraded in vivo over time. The bioabsorbable material mayinclude one or more of polylactide, poly-L-lactide (PLLA),poly-D-lactide (PDLA), polyglycolide (PGA), polydioxanone,polycaprolactone, polygluconate, polylactic acid-polyethylene oxidecopolymers, modified cellulose, collagen, poly(hydroxybutyrate),polyanhydride, polyphosphoester, poly(amino acids), poly(a-hydroxyacid), collagen or other connective proteins or natural materials,polycaprolactone, and copolymers of these materials as well ascomposites thereof and combinations of other biodegradable polymers.

A removal tool 300 is shown in FIG. 3. Removal tool 300 may extend froma proximal end 302 to a distal end 304. A side surface 306 may extendbetween proximal end 302 and distal end 304. The proximal end 302 anddistal end 304 each may include an attachment portion 308 configured tointerface with and couple to first support 102 and second support 104described above. The length of removal tool 300 between attachmentportions 308 may be substantially the same as the length of spacers 116.The attachment portions 308 may include recesses 310 disposed withinside surface 306. Mating features 312 may extend longitudinally towardone another and into recess 310 from opposing ends of the attachmentportion 308, and may correspond to the mating features 110 disposed onthe proximally-facing surface 106 and the distally-facing surface 108 ofthe support 102 and the second support 104. Mating features 312 may beprotrusions, rollers, wheels, bearings or other suitable members thatmay ride along a rail or track provided by the mating features 110 offirst support 102 and the second support 104. In some examples, matingfeatures 312 may be magnetic, and may be magnetically attracted to oneor more portions of first support 102 and second support 104, such as,e.g., mating features 110.

Tool 300 also may include a cutting member 314 that extends radiallyoutward from side surface 306. The cutting member 314 may be anysuitable surgical cutting tool, such as, e.g., a knife, blade, edge, orthe like. Cutting member 314 may include one or more other geometricfeatures such as, e.g., serrations, teeth, tapers, bevels or the like tofurther facilitate spearing, cutting, or slicing of cutting member 314through tissue. Cutting member 314 may have a cutting surface 330 thatextends from side surface 306 at a first end 332 and at a second end334. At least a portion of the cutting surface 330 may be spaced apartfrom the side surface 306. In the example shown in FIG. 3, cuttingsurface 330 is spaced from side surface 306 between first end 332 andsecond end 334. In other examples, cutting member 314 may be anelectrosurgical cutting tool, or may include other suitable energymodalities such as, e.g., laser or high intensity focused ultrasound(HIFU).

Removal tool 300 may be coupled to a controller 316, which may include aprocessor that is generally configured to accept information from thesystem and system components, and process the information according tovarious algorithms to produce control signals for controlling cuttingmember 314. The processor may accept information from the system andsystem components, including various temperature, impedance, or othersensors, and process the information according to various algorithms.The processor may be a digital IC processor, analog processor, or anyother suitable logic or control system that carries out the controlalgorithms. Controller 316 may include or may be otherwise coupled to asuitable power source (e.g., RF, laser, HIFU). Controller 316 also maybe configured to control the degree to which cutting member 314 extendsfrom side surface 306, or may otherwise control the depth of tissuethrough which cutting member 314 may penetrate. In some examples, thedepth of cutting member 314 may be controlled manually.

Removal tool 300 may be coupled to an actuator 318 configured to movethe removal tool 300 along a circumferential path around a body lumen,using first support 102 and/or second support 104 as guides. Actuator318 may be any suitable mechanism, and may include mechanical linkagesmanually operated by a user, or may include a motor operated by acontroller, such as, e.g., controller 316. Actuator 318 may beconfigured to move removal tool 300 in a first circumferential directionand a second circumferential direction that opposes the firstcircumferential direction. In one example, the operator could controlthe removal tool 300 by use of the endoscope and there may be noactuator 318 present. Actuator 318 may also be an array of piezoelectricmotors that interface with the support rings 102 and 104 and are drivenex vivo by a controller.

Tissue expander 100 may be movable from a collapsed configuration shownin FIG. 4 to a partially-collapsed, partially-expanded configurationshown in FIG. 5, to an expanded configuration shown in FIGS. 1 and 6.

Referring to FIG. 4, tissue expander 100 may be inserted into a lumen402 of an elongate member 400. Elongate member 400 may be flexible inorder to navigate tortuous anatomy within a patient, and may extend froma proximal end (not shown) toward a distal end 404. In some examples,elongate member 400 may be uniformly flexible, or may include portionshaving varied flexibility. For example, distal end 404 of elongatemember 400 may be more flexible than the proximal end of elongate member400. Elongate member 400 may include any suitable dimensions as is knownin the art, and may be used in place of or in combination with anytraditional medical scope, such as, e.g., an endoscope, a ureteroscope,a colonoscope, a hysteroscope, a uteroscope, a bronchoscope, or acystoscope. Elongate member 400 may be directly inserted into the bodyof a patient or may be extended over a guidewire using one or morelumens. Elongate member 400 also may be inserted into a laparoscopicport, a single incision port, an over-tube, a bouché, or any othersuitable member.

Tissue expander 100 may be delivered to a body lumen 410 by elongatemember 400 or by another suitable delivery system. Body lumen 410 may bea lumen of the colon, although other suitable body lumens are alsocontemplated. Body lumen 410 may be defined by a tissue wall 412, whichmay include an irregular topology or surface represented in the Figuresby a plurality of longitudinally spaced ridges 414 (or otherirregularities in tissue) that may extend radially inward from an innercircumference of the tissue wall 412 into the body lumen 410.

Distal end 404 may be positioned distally of target tissue 416 (whichmay be cancerous or potentially-cancerous tissue desired to be resected)as shown in FIG. 4. The second support 104 then may be deployed fromdistal end 404 and may expand automatically (e.g., self-expand) or maybe expanded by a suitable mechanism as set forth above (FIG. 5). Thedistal end 404 of elongate member 400 then may be retracted proximallyor otherwise positioned proximal to target tissue 416, at which pointfirst support 102 may be deployed from distal end 404. Once firstsupport 102 is deployed from distal end 404, first support 102 mayexpand radially to engage the tissue wall 412 proximally of targettissue 416, and spacers 116 also may urge toward their expandedconfigurations. First support 102 and second support 104 may engage theinner surface of tissue wall 412, and thus, when spacers 116longitudinally expand, the portion of tissue wall 412 disposed betweenfirst support 102 and second support 104 may be spread out to create asubstantially uniform, cylindrical surface (as shown in FIG. 6), so asto cause tissue irregularities, like ridges 414, to stretch and flatten.

First support 102 and second support 104 may be coupled to one anotherby flexible spacers 116 while disposed within elongate member 400.However, in other examples, first support 102 and second support 104 maybe uncoupled to one another while disposed within elongate member 400,and may be inserted separately into the body lumen 410. In suchexamples, a user may position second support 104 distally of targettissue 416, and subsequently position first support 102 proximally oftarget tissue 416. Once first support 102 and second support 104 areexpanded by the mechanisms set forth above, one or more spacers 116 maybe inserted between first support 102 and second support 104. Spacers116 then may be expanded until a desired distance is achieved betweenfirst support 102 and second support 104, which may be when, forexample, the surface of tissue wall 412 becomes substantiallycylindrical, or when first support 102 and second support 104 areseparated from each other by a distance approximately equal to thelength of the removal tool 300 between attachment portions 308.

Once the first support 102 and second support 104 are spaced apart fromone another by a desired distance (that, e.g., corresponds to thedistance between attachment portions 308), removal tool 300 may beinserted into body lumen 410 via, e.g., elongate member 400 or anothersuitable delivery member, and may be coupled with first support 102 andsecond support 104 as shown in FIG. 7. In order to couple removal tool300 to first support 102 and second support 104, the mating features 312of removal tool 300 may be aligned with the corresponding matingfeatures 110 of first support 102 and second support 104. Once securedto first support 102 and second support 104, a depth of cutting member314 may be set manually by the user or by controller 316 prior topositioning it over the target tissue 416. Controller 316 may be arotating rod extending the entire width of the tool, and may have teeththat engage with the cutting member 314 inside the tool. The rod couldbe rotated on either side of the tool to adjust the depth of the cuttingmember 314. The depth of the cutting member 314 may be set ex vivo basedon diagnostic information available to the operator but could also beactuated in vivo. The controller 316 may also be a screw or plunger thatapplies force from the top of the tool. Counter-force may be applied bya spring or other mechanism inside the tool that would tend to reducethe cutting depth. By increased the force from the top, the cuttingdepth may be increased. Controller 316 may be manually actuated or couldbe actuated by a piezoelectric motor controlled by an ex vivo driver.Removal tool 300 then may be actuated by actuator 300 along acircumferential path defined by the circumferences of first support 102and second support 104, removing tissue from tissue wall 412, includingtarget tissue 416, via cutting member 314.

In some examples, one or more of spacers 116 may be removed orrepositioned before cutting member 314 is used to remove tissue fromtissue wall 412. That is, because removal tool 300 and cutting member314 travel circumferentially about the body lumen via first support 102and second support 104, the presence of spacers 116 along thecircumference of the first support 102 and second support 104 mayinterfere with the removal of target tissue by blocking the path ofremoval tool 300 along the track provided by mating features 110. Insome examples, all of spacers 116 may be removed from the body lumen 410before or after removal tool 300 is positioned into the body lumen 410.In one example, all of the spacers 116 may be removed, and first support102 and second support 104 may be configured to retain their positionrelative to one another by one or more surface features or anchoringfeatures 118. In another example, only those spacers 116 necessary toclear a circumferential path for removal tool 300 may be removed.Spacers 116 also may be repositioned to create a circumferential pathfor removal tool 300 around body lumen 410. That is, spacers 116 may beconfigured to be moved along a circumferential path created by firstsupport 102 and second support 104. In such examples, spacers 116 may beslid along a track of mating feature 110 from a first circumferentialposition to a second circumferential position if access of the removaltool 300 to the targeted tissue 416 is blocked when a spacer 116 isdisposed in the first circumferential position.

The en bloc resected tissue may be removed from body lumen 410 byconventional mechanisms, such as, e.g., graspers, suction, or the like.Bleeding may be controlled using conventional methods after theresection is complete. The removal tool 300 then may be removed,followed by first support 102, second support 104, and spacers 116 (ifnot already removed).

In at least some examples of the present disclosure, the need tovisualize a cut and submucosa during the procedure may be eliminatedbecause the cut depth may be controlled by the cutting member 314. Theneed to inject saline or similar solutions to raise the target tissue ortumor also may be eliminated. In some examples of the presentdisclosure, this may result in fewer or no through-the-scope deviceexchanges being performed. The risk of damage to the muscularis also maybe reduced because of the increased control of the cutting depth.

A tissue expander 800 is shown in FIGS. 8-10 in a collapsedconfiguration, and in FIGS. 11-13 in an expanded configuration. Thetissue expander 800 may be movable between the collapsed configurationand the expanded configuration as set forth in further detail below. Thetissue expander may extend from a proximal end 802 toward a distal end804. The tissue expander 800 may include a support 806, which may be aring having a circular or other suitable cross-section.

A plurality of leg assemblies 808 may extend distally from the support806. Seven leg assemblies 808 a-g are shown in the example of FIG. 8,but additional or fewer leg assemblies 808 may be utilized. Each legassembly 808 may include a first leg 810 coupled to the support 806 at ajoint 812. Each leg assembly 808 further includes a second leg 814extending distally from first leg 810 at a joint 816. The first legs 810and second legs 814 may have any suitable length, such as, e.g., 1.0 cmand 4.0 cm respectively, although other suitable dimensions are alsocontemplated. In some examples, second legs 814 may be approximately 1.5to 10.0 times longer than first legs 810, although other suitable ratiosare also contemplated. First legs 810 and second legs 814 may be formedof any suitable biocompatible material including, but not limited tometals, alloys, plastics, or the like, and may include adhesive,bioadhesive, antibiotic, or other coatings. In some examples, thesurfaces of first legs 810 and second legs 814 may include one or moreanchoring features similar to anchoring features 118 described above, ormay be roughened, notched, slotted, etched, sand-blasted, coated orotherwise modified to provide a better gripping surface and attachmentto tissue walls surrounding a body lumen.

Joints 812 and 816 may be pivotable joints such as, e.g., a ball andsocket joint, a pivot joint, a swivel joint, or another suitablepivotable joint. Joint 812 may include a locking mechanism configured tolimit the proximal retraction of first legs 810. In some examples, thelocking mechanism of joint 812 may prevent the first legs 810 from beingretracted proximally of support 806. While first leg 810 is in theexpanded configuration, an angle θ (shown in perspective in FIG. 13) maybe measured between a longitudinal axis 818 of tissue expander 800 andfirst leg 810, and may be limited to 45 degrees or fewer. However, othersuitable configuration are also contemplated, including examples wherethe angle θ is from 15 degrees to 90 degrees. Joint 816 also may includea locking mechanism that is configured to maintain second leg 814substantially parallel to a longitudinal axis of the tissue expander 800in both the collapsed configuration and the expanded configuration.

In the collapsed configuration, the entirety of each leg assembly 808may be substantially parallel to a central longitudinal axis 822 of thetissue expander 100. That is, the first leg 810 and the second leg 814of each leg assembly 808 may be substantially parallel to the centrallongitudinal axis 822 of tissue expander 800 while in the collapsedconfiguration. As seen in FIGS. 8 and 9, most pairs of adjacent legassemblies 808 a-g may be in contact with one another, or may beseparated from one another by a small distance. However, at least onepair of adjacent leg assemblies (e.g., adjacent leg assemblies 818 a and818 g) may be separated from one another by a gap 820 in the collapsedconfiguration. In examples where there is some space or a gap betweenthe other adjacent leg assemblies 808, the length of gap 820 may besubstantially larger than those other gaps. In some examples, gap 820may be 1.5 to 1000 times larger than the gaps separating other adjacentleg assemblies, although other suitable ratios and proportions are alsocontemplated. Referring to FIG. 9, in the collapsed configuration, aradius r1 from the central longitudinal axis 822 of tissue expander 800to the outer circumference of leg assemblies 808 may be substantiallysimilar to a radius r2 from the central longitudinal axis 822 to theouter circumference of support 806. In some examples, r1 and r2 may be1.27 cm, while in other examples, r1 and r2 may be any suitabledimension such as, e.g., 0.1 cm to 10.0 cm. In some examples, the gap820 may be positioned adjacent to target tissue that will be resected.Once the tissue expander 800 is transitioned to the expandedconfiguration, the adjacent tissue may be substantially flattened tofacilitate resection.

Referring to FIGS. 10 and 13, tissue expander 800 may include anactuating mechanism 824 configured to reciprocally move tissue expander800 between the collapsed configuration and the expanded configuration.Actuating mechanism 824 may include a support 826, which, like support806 may be a ring support having a central lumen disposed therethrough.The support 826 may be coupled to one or more actuating members 828,such as, e.g., wires or the like configured to move support 826 from afirst position shown in FIG. 10 to a second position shown in FIG. 13.The support 806 and the support 826 each may include a lumen, and thoselumens may be collinear to enable the passage of an endoscope throughthe lumens. Support 806 and support 826 may separate form one anotherwhen moving from the collapsed configuration of FIG. 10 to the expandedconfiguration of FIG. 13. In some examples, both support 806 and support826 may be positioned or slid over an endoscope. One or more linkages830 (e.g., rigid cables or struts) may extend distally from support 826and may be coupled to an outer circumferential surface of each first leg810 of tissue expander 800. When a proximal force or tension is appliedto the actuating members 828, support 826 and linkages 830 may moveproximally (while support 806 remains stationary), pulling legassemblies 808 proximally to expand tissue expander 800 into theexpanded configuration shown in FIGS. 11-13. The proximal force may bereleased from actuating members 828 to cause tissue expander 800 torevert back to the collapsed configuration shown in FIG. 10. Tissueexpander 800 may be biased to collapsed configuration or to the expandedconfiguration.

In the expanded configuration, each first leg 810 may be radially offsetfrom center longitudinal axis 822 by 15 degrees to 90 degrees, and eachfirst leg 810 may be offset form center longitudinal axis 822 by thesame amount as every other first leg 810. Because each first leg 810 maybe radially offset from the central longitudinal axis 822 at an angle θ,the distance between central longitudinal axis 822 and leg 810 mayincrease linearly in the distal direction while tissue expander 800 isin the expanded configuration.

Referring to FIG. 12, in the expanded configuration, most adjacent legassemblies 808 may be spaced from one another by a first angle α, suchas, e.g., 10 to 60 degrees, while at least one other pair of adjacentleg assemblies 808 may be spaced apart from one another by a secondangle β that is greater than angle α, such as, e.g., 90 to 180 degrees.In one example, angle α may be 43.3 degrees and angle β may be 100degrees. The angles α and β may be defined in a plane that is normal tocentral longitudinal axis 822. Second legs 814 may be disposed at aradius r3 from central longitudinal axis 822 in the expandedconfiguration. Radius r3 may be 1.5 to 5.0 times larger than radii r1and r2, although other suitable ratios and proportions are alsocontemplated. Radius r3 may be 5.0 cm, or may be another suitabledimension, such as, e.g., 1.5 cm to 25 cm. The angle β may besubstantially similar in both the collapsed configuration and theexpanded configuration. In the expanded configuration, second legs 814may be unconnected and unattached to one another. That is, second legs814 may have free distal ends in the expanded configuration.

The tissue expander 800 may be positioned at a distal end of a scopevia, e.g., support 806. Once the tissue expander 800 is in the expandedconfiguration, an operator may detach the tissue expander 800 from thescope, allowing the scope to move freely within the body lumen to, e.g.,perform the cutting or other functions necessary for a resection. Thisarrangement may improve the visibility and use of tools through theworking channel of the scope. The tissue expander 800 may remaintethered to the scope to allow for easy removal of both the scope andthe tissue expander 800 once the procedure is completed.

In an alternative example, one or more of first leg 810 and second leg814 may be formed of a shape memory material, such as, e.g., nitinol. Inthis alternative example, joints 812 and 816 may not be pivotablejoints, but may instead be bends in a continuous piece of the shapememory material. In this example, the tissue expander 800 may bepre-bent into the expanded configuration as shown in FIGS. 11-13, andmay be constrained by a sheath (e.g., elongate member 400) in order tobe maintained in the collapsed configuration. When the elongate memberis positioned at the appropriate location in a body lumen, a pusher maybe used to apply a distal force to the proximal end of the tissueexpander 800 to deploy the tissue expander 800 from the elongate member.After completion of the procedure, the pusher member may be retracted,and the tissue expander 800 can be retracted within a lumen of theelongate member.

Tissue expander 800 may be positioned in a body lumen of a patient whiledisposed in the collapsed configuration, and while support 806 isattached to the distal end of an endoscope. Once a target area desiredto be resected is identified, the scope and tissue expander 800 may bemanipulated to place gap 820 adjacent to the target area. Once gap 820is adjacent the target area, a proximal force may be applied toactuating members 828, causing support 826 to retract proximallyrelative to support 806. This may cause the first legs 810 of theplurality of leg assemblies 808 to pivot proximally, which in turn maycause the tissue expander 800 to move from the collapsed configurationof FIGS. 8-10 to the expanded configuration of FIGS. 11-13. Thepositioning of gap 820 adjacent the target area may cause the tissuedisposed in the target area to substantially flatten when tissueexpander 800 is in the expanded configuration. The relatively largedistance between adjacent leg assemblies 808 a and 808 g that define gap820 (referring to FIG. 8) relative to other adjacent leg assemblies maycreate a relatively large flattened surface for a surgeon or user tooperate on. A resection tool (e.g., cutter, snare, or the like) may bepassed through a scope to remove tissue from the flattened surfacebetween adjacent leg assemblies 808 a and 808 g. When the resection iscompleted, the proximal force on actuating members 828 may be releasedcausing tissue expander 800 to revert to the collapsed configuration. Iftissue expander 800 was previously separated from the scope, it may bereattached, and both the scope and tissue expander 800 may be removedfrom the body.

As used herein, two objects and/or references (e.g., axes, planes, orthe like) may be “substantially parallel” to one another if they areparallel to one another, are offset from one another by less than 1degree, by less than 5 degrees, or by less than 10 degrees, as dictatedby, e.g., machining imperfections and the like.

Those skilled in the art will understand that the medical devices setout above can be implemented in any suitable body lumen (e.g., bloodvessels, the biliary tract, urological tract, gastrointestinal lumens,and the like) without departing from the scope of the disclosure asdefined by the claims. In particular, constructional details, includingmanufacturing techniques and materials, are well within theunderstanding of those of skill in the art and have not been set out inany detail here. These and other modifications and variations are wellwithin the scope of the present disclosure and can be envisioned andimplemented by those of skill in the art.

Other examples of the present disclosure will be apparent to thoseskilled in the art from consideration of the specification and practiceof the examples disclosed herein. It is intended that the specificationand examples be considered as exemplary only, and departures in form anddetail may be made without departing from the scope and spirit of thepresent disclosure as defined by the following claims.

What is claimed is:
 1. A medical device, comprising: a first support;and a plurality of leg assemblies coupled to the first support, whereinthe plurality of leg assemblies are circumferentially arranged about acentral longitudinal axis of the device, wherein at least one pair ofadjacent leg assemblies is separated from one another by a first angledefined in a plane that is normal to the central longitudinal axis ofthe device, and wherein remaining pairs of adjacent leg assemblies areseparated from one another by second angles defined in the plane thatare less than the first angle, wherein each of the plurality of legassemblies includes: a first joint connecting a corresponding legassembly to the first support; a first leg having a distal end and aproximal end coupled to and extending from the first support at thefirst joint, the first leg being configured to pivot relative to thefirst support via the first joint; a second joint disposed at the distalend of the first leg; and a second leg having a free distal end and aproximal end coupled to and extending distally from the distal end ofthe first leg at the second joint.
 2. The device of claim 1, wherein thefree distal ends of each of the second legs are unconnected to oneanother and to the first legs, the first angle is from 80 degrees to 120degrees, and each of the second angles is from 20 degrees to 60 degrees.3. The device of claim 1, wherein the first leg and the second leg ofeach of the plurality of leg assemblies are substantially parallel tothe central longitudinal axis when the device is in a collapsedconfiguration.
 4. The device of claim 1, wherein the device is movableto an expanded configuration, wherein in the expanded configuration, thefirst leg of each of the plurality of leg assemblies is transverse tothe central longitudinal axis, and the second leg of each of theplurality of leg assemblies is substantially parallel to the centrallongitudinal axis.
 5. The device of claim 4, further including: a secondsupport disposed proximally of the first support; and a plurality oflinkages extending from the second support, wherein at least one linkageof the plurality of linkages is coupled to each first leg of theplurality of leg assemblies, wherein, when a proximal force is appliedto the second support, the second support moves proximally relative tothe first support to cause the linkages to pull proximally on each firstleg of the plurality of leg assemblies, causing each first leg to pivotproximally via a respective first joint, and moving the device to theexpanded configuration.
 6. The device of claim 5, wherein the firstsupport and the second support each includes a lumen, and wherein thelumens of the first support and the second support are aligned to enablethe passage of an endoscope through the lumens.
 7. The device of claim1, wherein each first joint includes a locking mechanism configured tolimit a proximal retraction of a respective first leg.
 8. The device ofclaim 1, wherein the second leg is configured to pivot relative to thefirst leg via the second joint.
 9. The device of claim 1, wherein thefirst support includes a ring.
 10. The device of claim 1, wherein, in anexpanded configuration, a third angle between the central longitudinalaxis of the device and the first leg is from 15 degrees to 90 degrees.11. The device of claim 1, wherein the second joint includes a lockingmechanism that is configured to maintain the second leg substantiallyparallel to the central longitudinal axis of the device in both acollapsed configuration and an expanded configuration.
 12. The device ofclaim 1, wherein, in a collapsed configuration: a plurality of pairs ofadjacent leg assemblies are in contact with one another, or areseparated from one another by a first gap; and exactly one pair ofadjacent leg assemblies is separated from one another by a second gapthat is larger than the first gap.
 13. The device of claim 12, whereinthe second gap is 1.5 to 1000 times larger than the first gap.
 14. Thedevice of claim 1, wherein, in a collapsed configuration, a first radiusfrom the central longitudinal axis to an outer circumference of the legassemblies is substantially equal to a second radius from the centrallongitudinal axis to an outer circumference of the first support. 15.The device of claim 14, wherein the first radius is from 0.1 cm to 10.0cm.
 16. A medical device, comprising: a first support; and a pluralityof leg assemblies coupled to the first support, wherein the plurality ofleg assemblies are circumferentially arranged about a centrallongitudinal axis of the device, wherein each of the plurality of legassemblies includes: a first joint connecting a corresponding legassembly to the first support; a rigid first leg extending from thefirst joint; a second joint disposed at a distal end of the rigid firstleg; and a rigid second leg extending distally from the second joint;wherein the rigid first leg and the rigid second leg of each of theplurality of leg assemblies are substantially parallel to the centrallongitudinal axis when the device is in a collapsed configuration; andwherein the device is movable to an expanded configuration, and in theexpanded configuration, the rigid first leg of each of the plurality ofleg assemblies is transverse to the central longitudinal axis andconfigured to expand adjacent tissue outward from the centrallongitudinal axis, and the rigid second leg of each of the plurality ofleg assemblies is substantially parallel to the central longitudinalaxis and configured to flatten the expanded tissue.
 17. The device ofclaim 16, wherein, in the collapsed configuration: a plurality of pairsof adjacent leg assemblies are in contact with one another, or areseparated from one another by a first gap; and exactly one pair ofadjacent leg assemblies is separated from one another by a second gap,the second gap being larger than the first gap.
 18. A medical device,comprising: a first support including a central opening; and a pluralityof leg assemblies coupled to an outer circumference of the firstsupport, and disposed about the central opening, wherein each of theplurality of leg assemblies includes: a first joint connecting acorresponding leg assembly to the first support; a first leg extendingfrom the first joint, the first leg having a first length; a secondjoint disposed at a distal end of the first leg; and a second legextending distally from the second joint, the second leg having a secondlength that is greater than the first length; wherein, in a collapsedconfiguration: a plurality of pairs of adjacent leg assemblies are incontact with one another, or are separated from one another by a firstgap; and one pair of adjacent leg assemblies is separated from oneanother by a second gap, the second gap being larger than the first gap.19. The device of claim 18, wherein the second gap is 1.5 to 1000 timeslarger than the first gap.
 20. The device of claim 18, wherein exactlyone pair of adjacent leg assemblies is separated from one another by thesecond gap in the collapsed configuration; and wherein, in response totransitioning from the collapsed configuration to an expandedconfiguration, the first gap between the plurality of pairs of adjacentleg assemblies increases and the second gap between the one pair ofadjacent leg assemblies remains constant.